1. Field of the Invention
The present invention concerns a mammography installation or a mammography system of the type wherein the patient lies prone on a bed surface of a bed arrangement while x-ray images of the breast of the patient are generated.
2. Description of the Prior Art
In digital contrast agent mammography, differentiation is made between digital dynamic subtraction mammography and dual energy subtraction mammography.
In digital dynamic subtraction mammography, a reference or baseline exposure of the breast is produced by means of a digital mammography system. After a contrast agent injection, multiple contrast agent exposures are subsequently produced at predeterminable time intervals from exactly the same position. These are logarithmically subtracted from the blank exposure so that the contrast agent enrichment is visible.
In the temporary dual energy subtraction method, two x-ray exposures with respectively different photon energies are produced after the administration of a contrast agent comprising iodine, wherein the energy magnitudes of both radiation beams border the K-edge of iodine. Since the absorption properties differ due to the different energy magnitudes, after equalizing the exposure level and subsequent weighted, logarithmic subtraction of the two x-ray exposures, a contrast agent enrichment can likewise be presented.
For example, in the case of a digital, full-field mammogram (FFDM), one or more digital x-ray exposures are made of the respective breast after a respective repositioning of the patient, before the use of a contrast agent. Additional x-ray exposures of breast tissue are subsequently produced with contrast agent, respectively with a new repositioning of the patient. However, the generation of x-ray exposures of both breasts has the disadvantage that x-ray exposures of each breast must be generated separately. This extra time expenditure is accompanied by an increased physical stress due to the administration of contrast agent.